\begin{table}%t1
\caption{\label{tab1}Fine structure levels and the relative energies
of the target (core) ion Fe~XXI in wavefunction expansion of Fe~XX. The 
atomic structure calculations for the wavefunction employs 
spectroscopic set of configurations:
2s$^2$2p$^2$, 2s2p$^3$, 2p$^4$, 2s$^2$2p3s, 2s$^2$2p3p, 2s$^2$2p3d,
2s2p$^2$3s, 2s2p$^2$3p, 2s2p$^2$3d, 2p$^3$3s, and correlation
configurations: 2p$^3$3p, 2p$^3$3d, 2p$^3$4s, 2p$^3$4p, 2p$^3$4d, 
2s$^2$2p4s, 2s$^2$2p4p, 2s$^2$2p4d, 2s2p$^2$4s, 2s2p$^2$4p, 2s2p$^2$4d, 
and the Thomas-Fermi scaling parameters for the orbitals: $\lambda_{nl}
= 1.42$(1s), 1.25(2s), 1.15(2p), 1.25(3s), 1.15(3p), 1.17(3d), --1.20(4s), 
--1.20(4p), --1.2(4d).}
%\centering
\par
\begin{tabular}{rlrr}
\noalign{\smallskip}
\hline\hline
\noalign{\smallskip}
& Term & $J_t$ & $E_t$~(Ry) \\
 \noalign{\smallskip}
 \hline
 \noalign{\smallskip}
1 & 2s$^2$2p$^2$($^3$P) & 0 & 0.0 \\
2 & 2s$^2$2p$^2(^3$P) & 1 & 0.67297 \\
3 & 2s$^2$2p$^2(^3$P) & 2 & 1.0694 \\
4 & 2s$^2$2p$^2(^1$D) & 2 & 2.2286 \\
5 & 2s$^2$2p$^2(^1$S) & 0 & 3.3890 \\
6 & 2s2p$^3(^5$S$^{\rm o}$) & 1 & 4.4374 \\
7 & 2s2p$^3(^3$D$^{\rm o}$) & 1 & 7.0785 \\
8 & 2s2p$^3(^3$D$^{\rm o}$) & 2 & 7.0837 \\
9 & 2s2p$^3(^3$D$^{\rm o}$) & 3 & 7.3260 \\
10& 2s2p$^3(^3$P$^{\rm o}$) & 0 & 8.3507 \\
11& 2s2p$^3(^3$P$^{\rm o}$) & 1 & 8.4281 \\
12& 2s2p$^3(^3$P$^{\rm o}$) & 2 & 8.5871 \\
13& 2s2p$^3(^3$S$^{\rm o}$) & 1 & 9.9838 \\
14& 2s2p$^3(^1$D$^{\rm o}$) & 2 &10.268  \\
15& 2s2p$^3(^1$P$^{\rm o}$) & 1 &11.491  \\
16& 2s2p$^4(^3$P) & 2 &15.002  \\
17& 2s2p$^4(^3$P) & 1 &15.861  \\
18& 2s2p$^4(^3$P) & 0 &15.817  \\
19& 2s2p$^4(^1$D) & 2 &16.560  \\
20& 2s2p$^4(^1$S) & 0 &18.665  \\
\hline
\end{tabular}
\end{table}